Degreasing apparatus and method

ABSTRACT

Articles are degreased by being lowered into a zone of vapour originating from a pool of boiling solvent. The vapour condenses on the articles, dissolving oil and other impurities, and the impure solvent is allowed to flow into the pool of boiling solvent. The articles are now dipped into a pool of comparatively cold solvent. Finally, the articles are lifted up into the vapour zone, and the pure solvent formed by condensation on the articles is allowed to flow into the pool of comparatively cold solvent.

United States Patent [191 Holm DEGREASING APPARATUS AND METHOD [75] Inventor: Kunt Anders Holm, Skoghall,

Sweden [73] Assignee: Uddeholms Aktiebolag, Uddeholm,

Sweden [22] Filed: June 15, 1972 [21] Appl. No.: 263,206

[30] Foreign Application Priority Data July 22, 1971 Sweden 9447/71 [52] US. Cl 134/79, 134/11, 134/25, 134/31, 134/107, 134/133, 134/159 [51] Int. Cl B08b 3/04 [58] Field of Search 134/11, 25, 31, 78, 79, 134/105, 107, 109, 154, 159

[56] References Cited UNITED STATES PATENTS 2,571,581 l0/195l Kearney 134/31 [111 3,815,615 June 11, 1974 9/1971 Holm 134/79 4/1972 Holm ct al. 134/109 Primary Examiner-Morris O. Wolk Assistant Examiner-Dale Lovercheck Attorney, Agent, or Firm-Pierce, Scheffler & Parker 57 ABSTRACT Articles are degreased by being lowered into a zone of vapour originating from a pool of boiling solvent. The vapour condenses on the articles, dissolving oil and other impurities, and the impure solvent is allowed to flow into the pool of boiling solvent. The articles are now dipped into a pool of comparatively cold solvent. Finally, the articles are lifted up into the vapour zone, and the pure solvent formed by condensation on the articles is allowed to flow into the pool of comparatively cold solvent.

5 Claims, 3 Drawing Figures DEGREASING APPARATUS AND METHOD The invention relates to an apparatus for degreasing articles with the help of a solvent, preferably a chlorinated hydrocarbon, such as trichloroethylene or perchloroethylene. Degreasing apparatuses are known in which the objects are treated with a liquid solvent, or with the vapour from a boiling solvent, or with both.

The invention relates to an apparatus of the known type which comprises a degreasing tank, a first container for liquid solvent, located in the degreasing tank and intended for relatively cool solvent, a second container for liquid solvent, heating means to heat the solvent in the second container to boiling in order to provide a vapour zone of gaseous solvent above the first container, a condensor located in the vapour zone for condensation of solvent vapour, preferably located so that it defines the upper level of the vapour zone, and a transport means to transport the articles down through the vapour zone, through the solvent in the first container and up through the vapour zone. The object of the invention is to achieve an apparatus which permits more efficient degreasing than previously known apparatus of this type. According to the invention, this is achieved by arranging the first container to receive the relatively clean liquid solvent which is formed when the solvent vapour condenses on the condensor and on the articles as they pass up through the vapour zone, and by arranging the second container to receive the relatively unclean solvent which is formed when the solvent vapour condenses on the articles as they pass down through the vapour zone. The explanation of the satisfactory cleaning effect would appear to be that the articles are subjected to a pre-degreasing on their way down towards the first container with liquid solvent and that the unclean condensate which then runs off the articles is not permitted to mix'with the liquid solvent in this first container. The solvent in the first container can, therefore, be kept relatively clean. When the articles pass up through the vapour zone and are thus subjected to a final degreasing due to condensation of the solvent vapour, therefore, only a negligible amount of impurities has to be removed, and this final degreasing process will therefore be particularly effective.

In the following the invention will be further described with reference to the accompanying drawings.

FIGS. 1 and 2 show one embodiment of the apparatus according to the invention.

FIG. 3 shows a second embodiment.

The apparatus according to FIGS. 1 and 2 comprises a degreasing container 1 having rectangular cross section and provided with a lid 2. A container 3 is located in the bottom of the tank, for liquid solvent. This solvent can be brought to boil with the help of immersion heaters 4. The vapour from the solvent fills a vapour zone 5. In this vapour zone 5 is a container 6, open at the top, with a heat insulated bottom 7a and side walls 7b. This container 6 fills the entire cross-section of the degreasing tank 1, except for an opening 8 at one short side of the tank.

A wheel is also arranged in the degreasing tank 1, this wheel comprising a circular disc 9, an annular plate 10 and a perforated, cylindrical wall 11. The wheel is mounted on a horizontal shaft 12 and can be rotated in the direction of the arrow by means of a motor 13. The

lower part of the wheel extends down into the container 6. The wheel is divided into compartments 26 by means of a plurality of partition walls or shelves 14 extending substantially radially from the cylindrical wall 1 approximately to the inner edge of the annular plate 10. The inner edge part 15 of the shelf 14 is bent at a right angle in the opposite direction to the direction of rotation of the wheel. The outer edge part 16 of the shelf 14 extends through a slot in the perforated wall 11 and forms a drip-edge, the importance of which will be explained later on. The degreasing tank 1 also contains a condensor in the form of cooling tubes 19 placed in a pocket 20 which collects the condensate formed, the condensate then running down to the container 6 through a conduit 21. The upper edge of the pocket 20 will define the upper level 22 of the vapour zone, which should be located at the shaft 12 of the wheel, or slightly lower.

Articles 27 to be degreased are supplied to the wheel 9 11 by a conveyor 17 which extends into the wheel through the opening in the annular disc 10. The conveyor is in the form of an inclined sliding track which is so positioned that the articles 27 land on a shelf 14 when the shelf has arrived at approximately position 14a, that is in an approximately horizontal position.

Degreased articles are removed from the wheel 9-11 by a conveyor 18 which also extends through the opening in the annular plate 10. This conveyor 18 also comprises an inclined sliding track and is positioned so that the articles 27 slide off a shelf 14 down on to the conveyor 18 when the shelf is approximately in position 14b. In this position the bent edge section 15b of the shelf faces downwardly and does not therefore impede the movement of the articles.

The apparatus according to FIGS. 1 and 2 functions in the following manner. The unclean articles are carried by the wheel 9-11 down through the vapour zone 5. Here the vapour from the solvent condenseson the cold articles and the condensate runs off, carrying with it most of the fat, oil and other impurities. The unclean condensate runs along the shelf 14, through the openings in the perforated wall 11, and drips from the dripedge 16 through the opening 8 down into the boiling solvent in the container 3. The impurities thus increase in this solvent, which must be changed from time to time. The drip-edges 16 thus prevent the unclean condensate from running along the cylindrical wall 11 down into thecontainer 6. When the drip-edge 16 has reached the upper edge of the side wall 7b of the container 6, substantially all unclean condensate has run off and when the articles reach thesolvent in the container 6, they are substantially clean. However, some solid particles and other impurities which were not rinsed off by the condensate are removed in the container 6. The temperature of the solvent in the container 6 should suitably be 20 below the boiling point of the solvent, or lower. This low temperature is maintained partly since the container 6 receives relatively cool condensate from the condensor l9 and partly because the bottom 7a and wall 7b are heat-insulated. The solvent in the container 6 is gradually cleaned since the excess runs over the upper edge of the wall 7b, down into the container 3.

When the articles pass up through the vapour zone 5, vapour condenses on them and the last remnants of impurities are rinsed away. At the same time the articles are heated to the boiling point of the solvent. When the articles arrive above the vapour level 22 they are dry, and just after that they slide off the shelf 14 down on to the conveyor 18 on which they leave the apparatus.

The apparatus according to FIG. 3 is similar to the apparatus according to FIGS. 1 and 2 and corresponding parts have the same designations.The difference is that theapparatus according to FIG. 3 is provided with an endless chain conveyor 24 which is carried by wheels 25. At regular distances along the conveyor 24 containers 23 are provided for the articles to be degreased. The predegreasing takes place in position 23a, the unclean condensate then running down into the container 3. In position 23b the articles are in the solvent in the container 6, and in position 230 the final degreasing takes place in the solvent vapour.

What is claimed is: i

1 Apparatus for degreasing articles with the help of a solvent, such as trichloroethylene, which comprises a degreasing tank (I);

a first container (6) for liquid solvent, located in the degreasing tank (1) and intended for relatively cool solvent;

a second container (3) for liquid solvent;

heating means (4) to heat solvent in the second container (3) to boiling in order to provide a vapour zone (5) of gaseous solvent above the first container (6);

a condenser (19) located in such vapour zone (5) for condensation of solvent vapour, so located that it defines the upper level (22) of such vapour zone; and

a transport means consisting essentially of a wheel (9) having a perforated wall (11) and compartments (26) for goods to be cleaned, the wheel being arranged for rotation in one direction and to be partly in such vapour zone (5) and partly in solvent in the first container (6), the wheel (9-11) being so positioned that in part it extends directly over the second container (3) without intervention of the first container and is provided with dripedges (16) from which solvent condensing on the unclean articles drips down into the second container (3), said wheel (91 1 transporting articles down through vapour zone (5), through solvent in the first container 6) and up through such vapour zone (5),

said first container (6) being arranged to receive relatively clean liquid solvent formed when solvent vapour condenses on said condenser (19) and on the articles as they pass up through such vapour zone (5) and v said second container (3) being arranged to receive from said drip edges relatively unclean solvent formed when solvent vapour condenses on the articles as they pass down through such vapour zone (5).

2. The degreasing apparatus defined in claim 1 according to which a plurality of spaced shelves (14) form partition walls separating said compartments (26) from each other, said apparatus further including a f irst means for conveying articles to be degreased into said wheel and onto said shelves, and a second means for receiving degreased articles from said shelves and transporting same from the wheel.

3. The degreasing apparatus defined in claim 1, wherein a plurality of spaced shelves (14) form partition walls separating said compartments (26)v from each other, said shelves (14) extending substantially radially and having edge walls (15 extending substantially at right angles to said shelves in a direction oppov site to the direction of rotation of said wheel.

4. The degreasing apparatus defined in claim 1, according to which drip edges 16) of said shelves (14) extend through openings provided in the perforated cylindrical wall 11 of said wheel so as to direct unclean condensate into said second container (3).

5. The degreasing apparatus defined in claim 2, wherein said first and said second means are inclined chutes for the gravitational transport of such articles to and from said wheel. 

1. Apparatus for degreasing articles with the help of a solvent, such as trichloroethylene, which comprises a degreasing tank (1); a first container (6) for liquid solvent, located in the degreasing tank (1) and intended for relatively cool solvent; a second container (3) for liquid solvent; heating means (4) to heat solvent in the second container (3) to boiling in order to provide a vapour zone (5) of gaseous solvent above the first container (6); a condenser (19) located in such vapour zone (5) for condensation of solvent vapour, so located that it defines the upper level (22) of such vapour zone; and a transport means consisting essentially of a wheel (9) having a perforated wall (11) and compartments (26) for goods to be cleaned, the wheel being arranged for rotation in one direction and to be partly in such vapour zone (5) and partly in solvent in the first container (6), the wheel (9-11) being so positioned that in part it extends directly over the second container (3) without intervention of the first container and is provided with drip-edges (16) from which solvent condensing on the unclean articles drips down into the second container (3), said wheel (9-11), transporting articles down through vapour zone (5), through solvent in the first container (6) and up through such vapour zone (5), said first container (6) being arranged to receive relatively clean liquid solvent formed when solvent vapour condenses on said condenser (19) and on the articles as they pass up through such vapour zone (5) and said second container (3) being arranged to receive from said drip edges relatively unclean solvent formed when solvent vapour condenses on the articles as they pass down through such vapour zone (5).
 2. The degreasing apparatus defined in claim 1 according to which a plurality of spaced shelves (14) form partition walls separating said compartments (26) from each other, said apparatus further including a first means for conveying articles to be degreased into said wheel and onto said shelves, and a second means for receiving degreased articles from said shelves and transporting same from the wheel.
 3. The degreasing apparatus defined in claim 1, wherein a plurality of spaced shelves (14) form partition walls separating said compartments (26) from each other, said shelves (14) extending substantially radially and having edge walls (15) extending substantially at right angles to said shelves in a direction opposite to the direction of rotation of said wheel.
 4. The degreasing apparatus defined in claim 1, according to which drip edges (16) of said shelves (14) extend through openings provided in the perforated cylindrical wall 11 of said wheel so as to direct unclean condensate into said second container (3).
 5. The degreasing apparatus defined in claim 2, wherein said first and said second means are inclined chutes for the gravitational transport of such articles to and from said wheel. 